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The eyeball is located in a bony container - the orbita. The eye socket has the shape of a truncated tetrahedral pyramid, the apex of which is turned towards the skull. The depth of the orbit in adults is 4-5 cm, the horizontal diameter at the entrance to the orbit (aditus orbitae) is about 4 cm, the vertical diameter is 3.5 cm.
The orbit has four walls (upper, lower, outer and inner), three of which (inner, upper and lower) border the paranasal sinuses.
Bottom wall formed by the zygomatic bone, the orbital surface of the upper jaw and the orbital process of the palatine bone (Fig. 1). The lower wall covers the maxillary sinus, the inflammatory processes of which can quickly spread to the orbital tissue. The lower wall is most often exposed to blunt trauma (contusions); As a result, displacement may occur eyeball downwards, limiting its upward and outward mobility when the inferior oblique muscle (m. obliquus inferior) is pinched.
Top wall formed by the frontal bone, in the thickness of which there is a sinus (sinus frontalis), and the small wing of the sphenoid bone. On the frontal bone from the side of the orbit, at the outer edge, there is a small bony protrusion (spina trochlearis), to which a tendon (cartilaginous) loop is fixed, through which the tendon of the superior oblique muscle (lig. m, obliqui superioris) passes. In the frontal bone at the top and outside there is a fossa for the lacrimal gland (fossa glandulae lacrimalis). The upper wall of the orbit is located on the border with the anterior cranial fossa, which is very important to consider in case of injuries.
Inner wall formed: from below - by the upper jaw and palatine bone; above - part of the frontal bone; behind - the sphenoid bone; in front - by the lacrimal bone and the frontal process of the maxilla.
There is a posterior lacrimal crest in the lacrimal bone, and an anterior lacrimal crest in the frontal process of the maxilla. Between them there is a depression - the fossa of the lacrimal sac (fossa sacci lacrimalis), in which the lacrimal sac (saccus lacrimalis) is located. Pit size 7x13 mm; below it passes into the nasolacrimal duct (ductus nasolacrimalis) 10-12 mm long, which passes through the wall of the maxillary bone and ends 2 cm posterior to leading edge inferior nasal concha. When the wall is damaged, emphysema of the eyelids and orbits develops.
The inner, upper and lower walls of the orbit border on the paranasal sinuses, which often causes the spread of inflammation and the tumor process from them into the orbital cavity.
Outer wall- the most durable; it is formed by the zygomatic, frontal bones and the greater wing of the sphenoid bone.
In the walls of the orbit at its apex there are holes and slits through which large nerves and blood vessels 5-6 mm long (see Fig. 1).
Rice. 1. Structure of the orbit
Visual channel(canalis opticus) - a bone canal with a round hole with a diameter of 4 mm. Through it, the orbit communicates with the cranial cavity. The optic nerve (n. opticus) and the ophthalmic artery (a. ophthalmica) pass through the optic canal.
Superior orbital fissure(fissura orbitalis superior) is formed by the body of the sphenoid bone and its wings. Through it, the orbit connects to the middle cranial fossa. The gap is closed only by a thin connective tissue membrane, through which three branches of the optic nerve (n. ophthalmicus) pass - n. lacrimalis, n. nasoclliaris, n. frontalis, as well as the oculomotor nerve (n. oculomotorius); the superior ophthalmic vein (v. ophthalmica superior) emerges from the orbit through this gap. If the upper orbital fissure a complex of symptoms of the same name develops: complete ophthalmoplegia (lack of movement of the eyeball), ptosis (drooping of the upper eyelid), mydriasis (dilation of the pupil), tactile sensitivity disorder, dilation of the retinal veins, exophthalmos (prolongation of the eyeball).
Inferior orbital fissure(fissura orbitalis inferior) is formed by the lower edge of the large wing of the sphenoid bone and the body of the upper jaw. Through it, the orbit communicates with the pterygopalatine and temporal fossa. The gap is closed by a connective tissue membrane into which fibers of the orbital muscle (m. orbitalis) are woven, innervated by sympathetic nerve fibers. One of the two branches of the inferior ophthalmic vein (v. ophtalrmca interios) exits through this gap, and enters the orbit n. infraorbitalis and a. infraorbitalis, n. zygomaticus and rr. orbitalis from the pterygopalatine ganglion (gangl. pterygopalatinum).
Front and rear mesh openings(foramen ethmoidale anterius et posterius) - holes in the ethmoid plates. The nerves of the same name, arteries and veins (branches of the nasociliary nerve) pass through them.
Oval hole(foramen ovale) is located in the large wing of the sphenoid bone, connecting the middle cranial fossa with the infratemporal fossa. Passes through it mandibular nerve- n. n.andibularis (III branch of n. trigeminis).
On the inside, the orbit is covered with periosteum (periorbita), which is tightly fused with the bones that form it in the area of the canalis opticus. Here is the tendon ring (annulus tendineus communis Zinni), in which all the extraocular muscles begin, except for the inferior oblique.
To the fascia of the orbit in addition to the periosteum include:
Vagina of the eyeball(vagina bulbi s. Tenoni) covers the entire eyeball, except for the cornea and the exit site of the n. opticus. Its thickest part (2.5-3.0 mm) is located in the equator of the eye, where the tendons of the extraocular muscles pass, which acquire a dense connective tissue sheath here. Dense cords also extend from the equatorial zone, connecting Tenon’s capsule with the periosteum of the walls and the edges of the orbit, thus creating a membrane that fixes the eyeball in the orbit. Below the eyeball is the suspensory ligament of Lockwood, which is of great importance in maintaining the eyeball in the correct position as it moves.
Episcleral (Tenon's) space(spatium episclerale) is represented by loose episcleral tissue (this circumstance is often used for instillation of drugs and implantation of transposition materials for therapeutic purposes).
The orbital septum (septum orbitae) is the fifth movable wall of the orbit, limiting the cavity of the orbit when the eyelids close. It is formed by fascia that connects the orbital edges of the cartilage of the eyelids with the bony edges of the orbit. The orbital cavity is filled with a fatty body; it is separated from the periosteum by a slit-like space. Vessels and nerves pass through the orbit from the apex to its base.
The ophthalmic artery (a. ophtalmica) enters the orbit through the optic foramen (foramen optidum) and immediately splits into several branches:
Superior orbital fissure formed by the body of the sphenoid bone and its wings, connects the orbit with the middle cranial fossa.
Tightened a thin connective tissue film through which the three main branches of the optic nerve pass into the orbit - the lacrimal, nasociliary and frontal nerves, as well as the trunks of the trochlear, abducens and oculomotor nerves. The superior ophthalmic vein leaves it through the same gap.
If this area is damaged a characteristic symptom complex develops: complete ophthalmoplegia, i.e. immobility of the eyeball, drooping (ptosis) of the upper eyelid, mydriasis, decreased tactile sensitivity of the cornea and skin of the eyelids, dilation of the retinal veins and slight exophthalmos. However, “superior orbital fissure syndrome” may not be fully expressed when not all, but only individual nerve trunks passing through this fissure are damaged.
Eyelids form the palpebral fissure. They, in the form of movable flaps, cover the front surface of the eyeball, protecting it from harmful external influences. Sliding over the eye with blinking movements, the eyelids evenly distribute tears, maintaining the moisture of the cornea and conjunctiva and washing away small foreign bodies.
Eyelids join at the corners of the palpebral fissure by the internal and external ligaments.
In the inner corner of the palpebral fissure there is a small elevation - the lacrimal caruncle, which has the structure of the skin with sebaceous and sweat glands and hairs.
Free edges of eyelids about 2 mm thick fit tightly to each other. They distinguish between anterior and posterior ribs, intermarginal, i.e. intercostal space: Eyelashes grow on the anterior rib, into the bulbs of which excretory ducts open sebaceous glands Zeiss. Between the eyelashes there are modified sweat glands Mollya. The excretory ducts of the cartilage glands (meibomneous) open into the intermarginal space. Their fatty secretion lubricates the edges of the eyelids, promoting their tight fit.
Skin of the eyelids very thin, delicate and easy to fold. The subcutaneous tissue is very loose and almost completely devoid of fat. This explains the ease of occurrence and spread of edema, hemorrhages, air from bruises, local inflammatory processes, diseases cardiovascular system, kidneys, etc.
Two horizontal grooves are visible on the skin of the eyelids- upper and lower orbitopalpebral folds corresponding to the boundaries of the cartilages of the eyelids . The superior sulcus depends on the tone of the levator palpebrae superioris muscle. Levator The upper eyelid has 3 legs attached to the eyelid. The two legs of the muscle are innervated by the oculomotor nerve, the middle part of the muscle, consisting of smooth fibers, by the sympathetic nerve. Sympathetic nerve palsy causes mild ptosis, while oculomotor nerve palsy results in complete drooping of the eyelid.
The orbicularis eyelid muscle is located under the skin., in which the orbital and palpebral parts are distinguished.
Orbital fibers make a circle along the edge of the eye socket.
Palpebral part located on the eyelids, their contraction leads to the closure of the palpebral fissure during sleep and when blinking. When you close your eyes, both parts of the muscle contract.
Behind the palpebral part of the orbicularis eyelid muscle there is a dense connective plate, which is called cartilage, although it does not contain cartilage cells. Cartilage serves as a framework for the eyelids and gives them the appropriate shape. Found in the thickness of the cartilage meibomian glands, producing a fatty secretion that prevents tears from spilling over the edge of the eyelids. The pinpoint excretory ducts of these glands exit into the intermarginal space. The thinnest film of fatty secretion covers the thinnest layer of tears on the surface of the cornea, delaying its evaporation.
Eyelashes grow in 2-3 rows along the front edge of the eyelid. Near the root of each eyelash there are sebaceous and modified sweat glands, the excretory ducts of which open into the hair follicles of the eyelashes.
At the medial edge of the eyelids there is an elevation - the lacrimal papilla, at the top of which the lacrimal punctum gapes - the initial part of the lacrimal canaliculi.
The eyelids have an abundant network of widely anastomosing vessels ophthalmic (branches of the internal carotid artery) and maxillary (branches of the external carotid artery) arteries. They form arcades on the eyelids, providing them with good nutrition and regeneration (for injuries, operations).
Outflow venous blood occurs towards the veins of the face and orbit, between which there are anastomoses. There are no valves in the veins, and the blood circulates in different directions. As a result, the inflammatory process of the eyelids (abscess, phlegmon, barley, etc.) of the upper half of the face into the orbit and cavernous sinus and the development of purulent meningitis are possible.
Lymphatic vessels upper eyelids flow into lymph nodes, located in front auricle, lower eyelid - into nodes located at the level of the angle of the lower jaw
Topographically and anatomically, two layers are distinguished in the eyelid, or plates: musculocutaneous and conjunctival-cartilaginous. The border between them is the middle of the intercostal space in front of the ducts of the meibomian glands.
The inner surface of the eyelids is covered with conjunctiva. The conjunctiva covers the eyelids, the eyeball, and the cornea with a thin membrane. There are, respectively, the conjunctiva of the eyelids, the conjunctiva of the eyeball or sclera, and the conjunctiva of the transitional folds. That part of the conjunctiva of the eyelids, which, forming a vault, passes onto the eyeball, is called the conjunctiva of transitional folds, or vaults.
The conjunctiva performs important physiological functions . High sensitive innervation ensures its protective role. The secretion of the conjunctival glands constantly lubricates the surface of the eyeball and ensures trophism of the cornea. The barrier function of the conjunctiva is carried out by many lymphoid elements in the submucosa of the adenoid tissue.
Superior orbital fissure syndrome is a pathology that is characterized by complete paralysis of the internal and external muscles of the eye and loss of sensitivity of the upper eyelid, cornea, and part of the forehead. Symptoms may be caused by damage to the cranial nerves. Painful conditions arise as complications of tumors, meningitis and arachnoiditis. The syndrome is typical for elderly and middle-aged people; this pathology is rarely diagnosed in children.
The orbit, or eye socket, is a paired bony cavity in the skull that is filled with the eyeball and its appendages. Contains structures such as ligaments, blood vessels, muscles, nerves, lacrimal glands. The apex of the cavity is its deep zone, bounded by the sphenoid bone, occupying approximately a fifth of the entire orbit. The boundaries of the deep orbit are outlined by the wing of the main bone, as well as the orbital process of the plate of the palatine bone, the infraorbital nerve and the inferior orbital fissure.
The orbit is represented by three zones, each of which is limited by nearby structures.
The apex of the orbit is associated with the following structures:
The deep orbit has the following openings:
Deep orbit slots:
Large nerves and blood vessels pass through the holes and cracks into the cavity of the orbit.
Superior orbital fissure syndrome can be caused by the following factors:
The occurrence of the symptom complex of superior palpebral fissure syndrome is associated with damage to the nerves: oculomotor, abducens, trochlear, ophthalmic.
Risk factors for the pathogenesis of the disease include living in environmentally polluted regions, eating foods containing carcinogens, prolonged exposure to ultraviolet rays on the eyes.
The main manifestations and symptoms of the pathology are:
Some symptoms cause significant discomfort and are recorded by the patient, others are revealed during examination by an ophthalmologist and further examination. The disease is characterized by unilateral damage with preservation of the functions of the second, healthy eye.
A combination of several signs or individual ones indicate a pathological syndrome, while the inferior orbital fissure remains unchanged.
In the photo, patients exhibit eye asymmetry and ptosis of the affected organ.
Diagnosis of the disease is complicated by the fact that other ophthalmological problems have similar symptoms. The syndrome manifests itself in the same way as the following conditions:
To differentiate the pathology from other diseases with similar manifestations, it is necessary to conduct diagnostic examinations in ophthalmology and neurology:
After detecting the first manifestations of the syndrome, immediate consultation with specialists is required: an ophthalmologist and a neurologist. Since the pathology is caused by damage to structures located near the orbital fissure, therapy involves influencing them in order to eliminate the root cause. Self-medication can lead to worsening of the condition and the inability to provide effective medical care.
The fundamental method in the treatment of the syndrome is immunosuppressive therapy, which stops the body’s protective response in the case of an autoimmune nature of the disease. The low prevalence of the pathology does not allow large-scale research, but analysis of the available data allows us to conclude that the use of corticosteroids is rational. The attending physician may prescribe:
The drugs are administered intravenously or taken orally in tablet form. The effect of this treatment appears already on the third or fourth day. If there is no improvement, there is a high probability that the disease was misdiagnosed.
Further monitoring of the patient's condition is important, since the steroids used also help eliminate the symptoms of diseases and conditions such as carcinoma, lymphoma, aneurysm, chordoma, and pachymeningitis.
In addition to immunosuppressive therapy, there is treatment of the symptom complex, which is designed to alleviate the patient’s condition. Analgesics in the form of drops and tablets and anticonvulsants are prescribed.
Indicated as general strengthening agents vitamin complexes. Metabolic drugs are taken to regulate metabolic processes in the affected structures of the eye.
The orbit is a cavity in the skull irregular shape, resembling a pyramid. It is based on bone, around which ligaments, muscular apparatus, and fascial membranes are located. The eye is located directly in the orbital cavity, which is protected by all these structures from possible damage. It should be taken into account that if the impact force is very large, then even the inert orbital frame is not able to protect the eyeball from damage.
The orbit contains the following bones of the skull:
The strongest wall, in the formation of which thick bones take part, is the outer one. The thinnest wall is the inner one, which is why it is most often damaged.
Among anatomical formations the eye sockets secrete:
Among the main functions that the orbit performs are:
Symptoms of pathology of the orbital region can be quite varied:
Dislocation of the eyeball within the orbit is of several types:
To diagnose pathological changes in the orbit, several methods are used:
Let us remember once again that the orbit is the bone protection for the eyeball. In addition to bones, its composition includes muscles, ligaments, and connective tissue. The function of the orbit is not limited to protecting the eye; it also acts as a connecting link, which is made possible by transmitting information along nerve fibers.
The orbit itself can be susceptible to various pathological processes, among which are:
Most often, the orbit undergoes inflammatory changes. Among such pathologies, the following nosologies can be distinguished:
With a horizontal dimension of 40 mm, and vertical - 32 mm(Fig. 2.1.3).
Most of the outer edge (margo lateralis) and the outer half of the bottom edge (margo infraorbitalis) The eye sockets are formed by the zygomatic bone. The outer edge of the orbit is quite thick and can withstand heavy mechanical loads. When a bone fracture occurs in this area, it usually follows the
Rice. 2.1.3. Bones that form the eye socket:
/ - orbital process of the zygomatic bone; 2 - zygomatic bone; 3 - frontosphenoid process of the zygomatic bone; 4 - orbital surface of the greater wing of the sphenoid bone; 5 - large wing of the sphenoid bone; 6 - lateral process of the frontal bone; 7 - fossa of the lacrimal gland; 8 - frontal bone; 9 - visual aperture; 10 - supraorbital notch; // - trochlear fossa; 12 - ethmoid bone; 13 - nasal bone; 14 - frontal process of the maxilla; 15 - lacrimal bone; 16 - upper jaw; 17 - infraorbital foramen; 18 - palatine bone; 19 - infraorbital groove; 20 - inferior orbital fissure; 21 -zygomaticofacial opening; 22 -superiorbital fissure
seam propagation lines. In this case, the fracture occurs either along the line of the zygomatic-maxillary suture in a downward direction or downward-outward along the line of the zygomatic-frontal suture. The direction of the fracture depends on the location of the traumatic force.
The frontal bone forms the superior edge of the orbit (margo supraorbitalis), and its outer and inner parts participate in the formation of the outer and inner edges of the orbit, respectively. In newborns, the upper edge is sharp. It remains acute in women throughout life, and in men it rounds off with age. The supraorbital notch is visible on the upper edge of the orbit on the medial side. (incisura frontalis), containing the supraorbital nerve (n. supraorbitalis) and vessels. Anterior to the artery and nerve and slightly outward relative to the supraorbital notch is a small supraorbital foramen. (foramen supraorbitalis), through which the artery of the same name penetrates into the frontal sinus and the spongy part of the bone (arteria supraorbitalis).
Inner edge of the orbit (margo medialis orbitae) in the anterior sections it is formed by the maxillary bone, which gives off a process to the frontal bone.
The configuration of the inner edge of the orbit is complicated by the presence of lacrimal ridges in this area. For this reason, Whitnall suggests considering the shape of the inner edge as a wavy spiral (Fig. 2.1.3).
Lower edge of the orbit (margo inferior orbitae) formed half by the maxillary and half by the zygomatic bones. The infraorbital nerve passes through the lower edge of the orbit from the inside (p. infraorbitalis) and the artery of the same name. They exit onto the surface of the skull through the infraorbital foramen (foramen infraorbitalis), located somewhat medially and below the lower edge of the orbit.
2.1.3. Bones, walls and openings of the orbit
As stated above, the orbit is formed by only seven bones, which are also involved in the formation of the facial skull.
The medial walls of the orbits are parallel. They are separated from each other by the sinuses of the ethmoid and sphenoid bones. The lateral walls separate the orbit from the middle cranial fossa in the back and from the temporal fossa in the front. The orbit is located directly under the anterior cranial fossa and above the maxillary sinus.
Superior wall of the orbit(Paries superior orbitae)(Fig. 2.1.4).
The upper wall of the orbit is adjacent to the frontal sinus and the anterior cranial fossa. It is formed by the orbital part of the frontal bone, and posteriorly by the small wing of the sphenoid bone.
Bone formations of the orbit
Rice. 2.1.4. Superior wall of the orbit (after Reeh et al., 1981):
/ - orbital wall of the frontal bone; 2 - fossa of the lacrimal gland; 3 - anterior ethmoidal opening; 4 - greater wing of the sphenoid bone; 5 - superior orbital fissure; 6 - lateral orbital tubercle; 7 - trochlear fossa; 8 - posterior crest of the lacrimal bone; 9 - anterior crest of the lacrimal bone; 10 - sutura notra
The sphenoid-frontal suture runs between these bones (sutura sphenofrontalis).
On the upper wall of the orbit there are a large number of formations that play the role of “marks” used during surgical interventions. The fossa of the lacrimal gland is located in the anterolateral part of the frontal bone (fossa glandulae lacrimalis). The fossa contains not only the lacrimal gland, but also a small amount of fatty tissue, mainly in the posterior part (accessory fossa Roch on-Duvigneaud). From below, the fossa is limited by the zygomaticofrontal suture (s. fronto-zigomatica).
The surface of the bone in the area of the lacrimal fossa is usually smooth, but sometimes roughness is detected at the site of attachment of the suspensory ligament of the lacrimal gland.
In the anteromedial part, approximately at a distance of 5 mm from the edge, the trochlear fossa and trochlear spine are located (fovea trochlearis et spina trochlearis), on the tendon ring of which the superior oblique muscle is attached.
The supraorbital nerve, which is a branch of the frontal branch, passes through the supraorbital notch, located on the upper edge of the frontal bone. trigeminal nerve.
At the apex of the orbit, directly at the lesser wing of the sphenoid bone, the optic foramen is located - the entrance to the optic canal (canalis opticus).
The upper wall of the orbit is thin and fragile. It thickens to 3 mm in the place where it is formed by the small wing of the sphenoid bone (ala minor os sphenoidale).
The greatest thinning of the wall is observed in cases where the frontal sinus is extremely developed. Sometimes resorption occurs with age bone tissue top wall. In this case, the periorbita is in contact with the hard meninges anterior cranial fossa.
Since the upper wall is thin, it is in this area that a bone fracture occurs during injury, with the formation of sharp bone fragments. Through the upper wall, various pathological processes (inflammation, tumors) developing in the frontal sinus spread into the orbit. It is also necessary to pay attention to the fact that the upper wall is located on the border with the anterior cranial fossa. This circumstance is of great practical importance, since injuries to the upper wall of the orbit are often combined with brain damage.
Inner wall of the orbit(Paries medialis orbitae)(Fig. 2.1.5).
The inner wall of the orbit is the thinnest (thickness 0.2-0.4 mm). It is formed by 4 bones: the orbital plate of the ethmoid bone (lamina orbitalis os ethmoi-dale), frontal process of the maxilla (processus frontalis os zigomaticum), tear braid
Rice. 2.1.5. Inner wall of the orbit (after Reeh et al., 1981):
1 - anterior lacrimal ridge and frontal process of the maxilla; 2 - lacrimal fossa; 3 - posterior lacrimal ridge; 4 - lamina papyracea ethmoid bone; 5 - anterior ethmoidal opening; 6 - optic foramen and canal, superior orbital fissure and spina recti lateralis; 7- lateral angular process of the frontal bone; 8 - inferoorbital margin with zygomaticofacial foramen located on the right
Chapter 2. ORBITS AND AUXILIARY APPARATUS OF THE EYE
Tew and lateral orbital surface of the sphenoid bone (fades orbitalis os sphenoidalis), located most deeply. In the area of the suture between the ethmoid and frontal bones, the anterior and posterior ethmoidal foramina are visible (foramina ethmoidalia, anterius et pos-terius), through which the nerves and vessels of the same name pass (Fig. 2.1.5).
A tear trough is visible in the anterior part of the inner wall (sulcus lacrimalis), continuing into the fossa of the lacrimal sac (fossa sacci lacrimalis). It contains the lacrimal sac. As the tear trough moves downward, it becomes the nasolacrimal canal. (glander-lis nasolacrimalis).
The boundaries of the lacrimal fossa are outlined by two ridges - the anterior and posterior lacrimal ridges (crista lacrimalis anterior et posterior). The anterior lacrimal ridge continues downwards and gradually passes into the lower edge of the orbit.
The anterior lacrimal ridge is easily palpable through the skin and is a mark during operations on the lacrimal sac.
As stated above, the main part of the inner wall of the orbit is represented by the ethmoid bone. Since it is the thinnest of all the bone formations of the orbit, it is through it that the inflammatory process most often spreads from the sinuses of the ethmoid bone to the tissue of the orbit. This can lead to the development of cellulite, orbital phlegmon, thrombophlebitis of the orbital veins, toxic optic neuritis, etc. Acutely developing ptosis often occurs in children. The inner wall is also where tumors spread from the sinus to the orbit and vice versa. It is often destroyed during surgical interventions.
The inner wall is somewhat thicker only in the posterior sections, especially in the area of the body of the sphenoid bone, as well as in the area of the posterior lacrimal crest.
The ethmoid bone, which participates in the formation of the internal wall, contains numerous air-containing bone formations, which may explain the rarer occurrence of fractures of the medial wall of the orbit than the thick floor of the orbit.
It is also necessary to mention that in the area of the ethmoidal suture, anomalies in the development of bone walls often occur, for example, congenital “gaping,” which significantly weakens the wall. In this case, the bone tissue defect is covered with fibrous tissue. Weakening of the inner wall also occurs with age. The reason for this is atrophy of the central areas of the bone plate.
In practical terms, especially when performing anesthesia, it is important to know the location of the anterior and posterior ethmoidal foramina through which the branches of the ophthalmic artery pass, as well as the branches of the nasociliary nerve.
The anterior ethmoidal openings open at the anterior end of the frontoethmoidal suture, and the posterior ones - near the posterior end of the same suture (Fig. 2.1.5). Thus, the front holes lie at a distance of 20 mm behind the anterior lacrimal ridge, and the posterior ones - at a distance of 35 mm.
The optic canal is located deep in the orbit on the inner wall. (canalis opticus), connecting the orbital cavity with the cranial cavity.
Outer wall of the orbit(Paries latera-lis orbitae)(Fig. 2.1.6).
The outer wall of the orbit in its posterior section separates the contents of the orbit and the middle cranial fossa. In front it borders with the temporal fossa (fossa temporalis), performed by the temporalis muscle (i.e. temporalis). It is delimited from the upper and lower walls by orbital fissures. These boundaries extend anteriorly to the sphenoid-frontal (sutura spheno-frontalis) and zygomaticomaxillary (sutura zi-gomaticomaxilare) seams (Fig. 2.1.6).
The posterior section of the outer wall of the orbit is formed only by the orbital surface of the greater wing of the sphenoid bone, and the anterior section is formed by the orbital surface of the zygomatic bone. Between them there is a sphenoid-zygomatic suture (sutura sphenozigomatica). The presence of this suture greatly simplifies orbitotomy.
Rice. 2.1.6. Outer wall of the orbit (after Reeh et al., 1981):
1 - frontal bone; 2 - greater wing of the sphenoid bone; 3 - zygomatic bone; 4 - superior orbital fissure; 5 - spina recti la-teralis; 6- inferior orbital fissure; 7 - the opening through which the branch passes from the zygomaticoorbital nerve to the lacrimal gland; 8 - zygomaticoorbital foramen
Bone formations of the orbit
On the body of the sphenoid bone, at the junction of the wide and narrow parts of the superior orbital fissure, there is a small bony protrusion (spike) (spina recti lateralis), from which the external rectus muscle begins.
On the zygomatic bone, near the edge of the orbit, there is a zygomaticoorbital foramen (/. zigomaticoorbitale), through which the branch of the zygomatic nerve leaves the orbit (p. zigomatico-orbitalis), heading towards the lacrimal nerve. The orbital eminence is also found in this area (eminentia orbitalis; orbital tubercle of Withnell). The external ligament of the eyelid, the external “horn” of the levator, and Lockwood’s ligament are attached to it (lig. suspensorium), orbital septum (septum orbitale) and lacrimal fascia (/. lacrimalis).
The outer wall of the orbit is the place of easiest access to the contents of the orbit during various surgical interventions. The spread of the pathological process to the orbit on this side is extremely rare and is usually associated with diseases of the zygomatic bone.
When performing an orbitotomy, the ophthalmic surgeon should know that the posterior edge of the incision is at a distance of 12-13 from the middle cranial fossa mm in men and 7-8 mm in women.
Inferior wall of the orbit(Paries inferior orbitae)(Fig. 2.1.7).
The bottom of the eye socket is also the roof maxillary sinus. This proximity is important from a practical point of view, since diseases of the maxillary sinus often affect the orbit and vice versa.
The lower wall of the orbit is formed by three bones: the orbital surface of the upper jaw (fades orbitalis os maxilla), occupying most of the floor of the orbit, the zygomatic bone (os zigomaticus) and the orbital process of the palatine bone (processus orbitalis os zigomaticus)(Fig. 2.1.7). The palatine bone forms a small area at the back of the eye socket.
The shape of the lower wall of the orbit resembles an equilateral triangle.
Between the inferior edge of the orbital surface of the sphenoid bone (fades orbitalis os sphenoidalis) and the posterior edge of the orbital surface of the maxillary bone (fades orbitalis os maxilla) the inferior orbital fissure is located (fissura orbitalis inferior). A line that can be drawn through the axis of the inferior orbital fissure forms the outer border of the inferior wall. The internal border can be determined along the anterior and posterior ethmoid-maxillary sutures.
On the side edge bottom surface the maxillary bone begins the infraorbital groove (groove) (sulcus infraorbitalis), which, as we move forward, turns into a channel (canalis infraorbitalis). They contain
Rice. 2.1.7. Inferior wall of the orbit (after Reeh et al., 1981):
I- lower orbital margin, maxillary part; 2 - infraorbital foramen; 3 - orbital plate of the upper jaw; 4 - inferior orbital groove; 5 - orbital surface of the greater wing of the sphenoid bone; 6 - marginal process of the zygomatic bone; 7 - lacrimal fossa; 8 - inferior orbital fissure; 9 - origin of the inferior oblique muscle
lies the infraorbital nerve (n. infraorbitalis). In the embryo, the infraorbital nerve lies freely on the bony surface of the orbit, but gradually sinks into the rapidly growing maxillary bone.
The external opening of the infraorbital canal is located under the lower edge of the orbit at a distance of 6 mm(Fig. 2.1.3, 2.1.5). In children this distance is much less.
The lower wall of the orbit has different densities. It is denser near and somewhat outside the infraorbital nerve. The inside wall becomes noticeably thinner. It is in these places that post-traumatic fractures are localized. The lower wall is also the site of spread of inflammatory and tumor processes.
Visual channel(Canalis opticus)(Fig. 2.1.3, 2.1.5, 2.1.8).
The optic foramen is located slightly inward of the superior orbital fissure, which is the beginning of the optic canal. The optic foramen is separated from the superior orbital fissure by the area connecting the lower wall of the lesser wing of the sphenoid bone, the body of the sphenoid bone with its lesser wing.
The opening of the optic canal facing the orbit has dimensions of 6-6.5 mm in the vertical plane and 4.5-5 mm in horizontal (Fig. 2.1.3, 2.1.5, 2.1.8).
The optic canal leads to the middle cranial fossa (fossa cranialis media). Its length is 8-10 mm. The axis of the optic canal is directed downward and outward. Rejection of this
Chapter 2. ORBITS AND AUXILIARY APPARATUS OF THE EYE
Rice. 2.1.8. Apex of the orbit (after Zide, Jelks, 1985):
1 - inferior orbital fissure; 2 - round hole; 3 - superior orbital fissure; 4 - optic foramen and optic canal
axis from the sagittal plane, as well as downwards, relative to the horizontal plane, is 38°.
The optic nerve passes through the canal (p. opticus), ophthalmic artery (a. ophthalmica), immersed in the optic nerve sheath, as well as the trunks of the sympathetic nerves. After entering the orbit, the artery lies below the nerve, and then crosses the nerve and is located outside.
Since the position of the ophthalmic artery, the canal takes the shape of a horizontal oval in the posterior section and a vertical oval in the anterior section.
Already by three years old the visual canal reaches normal sizes. Its diameter is more than 7 mm it is already necessary to consider it a deviation from the norm and assume the presence of a pathological process. A significant increase in the optic canal is observed with the development of various pathological processes. In young children, it is necessary to compare the diameter of the optic canal on both sides, since it has not yet reached its final size. If different diameters of the visual canals are detected (at least 1 mm) one can fairly confidently assume the presence of an anomaly in the development of the optic nerve or a pathological process localized in the canal. In this case, optic nerve gliomas, aneurysms in the area of the sphenoid bone, and intraorbital spread of tumors of the optic chiasm are most often found. It is quite difficult to diagnose intratubular meningiomas. Any long-term optic neuritis may indicate the possibility of developing intratubular meningioma.
A large number of other diseases lead to expansion of the visual canal. This benign hyperplasia arachnoid membrane, fungal infections (mycoses), granulomatous inflammatory reaction (syphilitic gumma, tuberculoma). Canal expansion also occurs in sarcoidosis, neurofibroma, arachnoiditis, arachnoid cyst and chronic hydrocephalus .
Narrowing of the canal is possible when fibrous dysplasia or fibroma of the sphenoid bone.
Superior orbital fissure(Fissura orbitalis superior).
The shape and size of the superior orbital fissure varies significantly between individuals. It is located on the outside of the optic opening at the apex of the orbit and has the shape of a comma (Fig. 2.1.3, 2.1.6, 2.1.8, 2.1.9). It is limited by the small and large wings of the sphenoid bone. The upper part of the superior orbital fissure is narrower on the lateral side than on the medial side and below. At the junction of these two parts is the spine of the rectus muscle. (spina recti).
The oculomotor, trochlear nerves, the first branch of the trigeminal nerve, the abducens nerve, the superior orbital vein, the recurrent lacrimal artery, and the sympathetic root of the ciliary ganglion pass through the superior orbital fissure (Fig. 2.1.9).
Common tendon ring (anulus tendi-neus communis; ring of Zinn) is located between the superior orbital fissure and the optic
Rice. 2.1.9. Location of structures in the region of the superior orbital fissure and ring of Zinn (after Zide, Jelks, /985):
1 - external rectus muscle; 2 -superior and inferior branches of the oculomotor nerve; 3 - frontal nerve; 4 - lacrimal nerve; 5 - trochlear nerve; 6 - superior rectus muscle; 7 - nasociliary nerve; 8 - levator of the upper eyelid; 9 - superior oblique muscle; 10 - abducens nerve; // - internal rectus muscle; 12 - inferior rectus muscle
Bone formations of the orbit
Channel. Through the ring of Zinn, the optic nerve, ophthalmic artery, superior and inferior branches of the trigeminal nerve, nasociliary nerve, abducens nerve, sympathetic roots of the trigeminal ganglion enter the orbit and are thereby located in the muscular funnel (Fig. 2.1.8, 2.1.9).
Immediately below the ring in the superior orbital fissure passes the superior branch of the inferior ophthalmic vein (v. ophthalmica inferior). Outside the ring, on the lateral side of the superior orbital fissure, the trochlear nerve passes (p. trochlearis), superior ophthalmic vein (v. ophthalmica superior), as well as the lacrimal and frontal nerves (paragraphs lacrimalis et frontalis).
Widening of the superior orbital fissure may indicate the development of various pathological processes, such as aneurysm, meningioma, chordoma, pituitary adenoma, benign and malignant tumors eye sockets
Sometimes an inflammatory process of unknown nature develops in the area of the superior orbital fissure (Talasa-Hant syndrome, painful ophthalmoplegia). Inflammation may spread to the nerve trunks leading to the external muscles of the eye, which is the cause of the pain that occurs with this syndrome.
Inflammatory process in the area of the superior orbital fissure can lead to disruption of the venous drainage of the orbit. The consequence of this is swelling of the eyelids and eye sockets. Tuberculous encephalic periostitis, spreading to structures located in the intraorbital fissure, has also been described.
Inferior orbital fissure(Fissura orbitalis inferior)(Fig. 2.1.7-2.1.10).
The inferior orbital fissure is located in the posterior third of the orbit between the bottom and the outer wall. Externally, it is limited by the greater wing of the sphenoid bone, and on the medial side by the palatine and maxillary bones.
The axis of the infraorbital fissure corresponds to the anterior projection of the optic foramen and lies at a level corresponding to the lower edge of the orbit.
The inferior orbital fissure extends forward more than the superior orbital fissure. It ends at a distance of 20 mm from the edge of the eye socket. It is this point that is the landmark of the posterior border when performing subperiosteal removal of the bone of the lower wall of the orbit.
Directly below the inferior orbital fissure and on the outside of the orbit is the pterygopalatine fossa (fossa pterygo-palatina), and in front - the temporal fossa (fossa temporalis), performed by the temporal muscle (Fig. 2.1.10).
Blunt trauma to the temporal muscle can lead to hemorrhage into the orbit as a result of destruction of the vessels of the pterygopalatine fossa.
Rice. 2.1.10. Temporal, infratemporal and pterygopalatine fossa:
/ - temporal fossa; 2 - pterygopalatine fossa; 3 - oval hole; 4 - pterygopalatine foramen; 5 - inferior orbital fissure; 6 - eye socket; 7 - zygomatic bone; 8 - alveolar process of the maxilla
Behind the lower orbital fissure in the large wing of the main bone there is a round hole (foramen rotundum), connecting the middle cranial fossa with the pterygopalatine fossa. Through this opening, branches of the trigeminal nerve, in particular the maxillary nerve, penetrate into the orbit (n. maxillaris). When leaving the foramen, the maxillary nerve gives off a branch - the infraorbital nerve (p. infraorbi-talis), which together with the infraorbital artery (a. infraorbitalis) penetrates the orbit through the infraorbital fissure. Subsequently, the nerve and artery are located under the periosteum in the infraorbital groove (sulcus infraorbitalis), and then pass into the infraorbital canal (foramen infraorbitalis) and extend onto the facial surface of the maxillary bone at a distance of 4-12 mm below the middle of the edge of the orbit.
Through the inferior orbital fissure from the infratemporal fossa (fossa infratemporalis) The zygomatic nerve also penetrates the orbit (n. zigo-maticus), minor branch of the pterygopalatine ganglion (g an g- sphenopalatina) and veins (inferior ophthalmic), draining blood from the orbit to the pterygoid plexus (plexus pterygoideus).
In the orbit, the zygomatic nerve divides into two branches - the zygomatic-facial (g. zigomaticofacialis) and zygomaticotemporal (p. zigomaticotemporalis). Subsequently, these branches penetrate into the canals of the same name in the zygomatic bone on the outer wall of the orbit and branch in the skin of the zygomatic and temporal regions. From the zygomaticotemporal nerve towards the lacrimal gland, the
Chapter 2. ORBITS AND AUXILIARY APPARATUS OF HAAZ
The nerve trunk carries secretory fibers.
The inferior orbital fissure is closed smooth muscle Muller. In lower vertebrates, contracting this muscle leads to protrusion of the eye.
